Electrical switch



, May 13, 1941. c. H. REYNOLDS ELECTRICAL SWITCH Filed June 17, 1938 3Sheets-Sheet 1 0 8 6 d ,4 Q A 0 c ,7 Q Q ra v 4 1 Z J .6 3 5 5 a a 2% w5 \A 1 2 INVENTOR.

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y 1941' c. H. REYNOLDS 2,241,828

ELECTRICAL SWITCH Filed June 17. 1938 3 Sheets-Sheet 2 INVENTOR.

CM m @w ATTORNEY.

y 1941- c. H. REYNOLDS 2,241,828

ELECTRICAL SWITCH Filed June 17, 1938 s Sheets-sheaf a INVENTOR.

8AM! 4. 2,1244, C} M CMACLA LQ ATTORNEY.

Patented May 13, 1941 ELECTRICAL SWITCH Charles H. Reynolds, Malden,Mass, assignor to Albert & J. M. Anderson Manufacturing Company, SouthBoston, Mass., a corporation of Massachusetts Application June 17, 1938,Serial No. 214,261

6 Claims.

This invention relates to an electrical switch and more particularly toan electrical switch of the type enclosed within a casing and havingprovision for receiving a terminal plug.

The invention has for an object to provide a novel and improvedelectrical switch of the character specified in which novel and superiorlocking mechanism is provided to retain the terminal plug in thereceptacle when the switch is closed.

Another object of the invention is to provide a. novel and improvedelectrical switch of the character specified in which the receptacle isprovided with locking mechanism adapted to engage the polarizing key ofa standard terminal plug and to utilize the polarizing key as a look ingmember whereby to prevent withdrawal of the terminal plug when theswitch is closed.

A further object of the invention is to provide a novel and superiorswitch of the character specified in which provision is made forpreventing the operation of the switch unless the terminal plug isinserted to its full depth into the receptacle and for preventinginsertion of the plug into the receptacle should the switchinadvertently become closed.

With these objects in view and such others as may hereinafter appear,the invention consists in the electrical switch and in the variousstructures, arrangements and combinations of parts hereinafter describedand particularly defined ln the claims at the end of this specification.

In the drawings illustrating the preferred embodiment of the invention,Fig. 1 is a longitudinal sectional view of a switch embodying thepresent invention; Fig. 2 is a view looking in the direction of thearrows 2-2 in Fig. 1; Fig. 3 is a view of a plug in position to beinserted into the receptacle in Fig. 1; Fig. 4 is a view similar to Fig.1 with the plug inserted and the switch closed; Fig. 5 is an enlargeddetail view looking in the direction of the arrows 5-5 in Fig. 4, andFig. 6 is a side elevation of the switch casing.

In general, the invention contemplates a novel and improved electricalswitch provided with a receptacle for the reception of a terminal plugand in which provision is made for employing the standard polarizing keyof the conventional terminal plug as a locking member when the plug isinserted into the receptacle. In the preferred embodiment of theinvention, a springpressed latch is adapted to be yieldingly urgedbehind the polarizing key when the plug is inserted to its full depthinto the receptacle, and

provision is made for retaining the latch in its locking position whenthe switch is closed whereby to prevent withdrawal of the plug until theswitch is again opened. Provision is also preferably made in thepreferred embodiment of the invention for preventing the operation ofthe switch member unless the plug is inserted to its full depth into thereceptacle and for preventing insertion of the plug in the receptacleunless the switch is open to the end that it would be impossible toinsert the plug should the switch in some manner become closed withoutthe plug in place. In the illustrated embodiment of the invention,provision is made for insuring the introduction of the plug into thereceptacle in predetermined definite relation whereby to assurealignment of the polarizing key with its locking pawl.

Referring now to the drawings in which the preferred embodiment of theinvention is illustrated, l0 represents a casing in which a switch,indicated generally at H, is enclosed. The casing I0 is provided withasocket or receptacle l2 adapted to receive a terminal plug l4 providedwith a standard polarizing key IS. The switch ll may preferably comprisethe conventional stationary contact jaws l6 mounted upon an insulatedbase l8, adapted to cooperate with a movable blade 20 secured to a stud22 journaled in the casing ill. The stud 22, as herein shown. ispreferably provided with an operating handle 24 fixed thereon.

As herein illustrated, provision is made for employing the polarizingkey l5 as a locking member to retain the plug in the receptacle and tothis end a latch member 28, pivotally mounted on a stud 28, is normallydisposed in the path of the plug l4 and the polarizing key IS. The

latch member 26 is yieldingly urged in a clockwise direction, viewingFigs. 1 and 4 by a coil spring 29 encircling the stud 28, having one endsecured in the latch member 26 and the other end in a stationary part ofthe casing It. In order to limit the clockwise movement of the latchmember, an extension 30 is provided, arranged to normally engage a hub32. In operation, when the plug I4 is inserted into the receptacle, thepolarizing key l5 engages the latch member 26 and yieldingly urges thelatter in a counter-clockwise direction until the plug is fully seated.whereupon the latch snaps into place behind the polarizing key.

In the preferred embodiment of the invention, provision is made forlocking the latch member 26 in its plug retaining position to preventwithdrawal of the latter when the switch II is moved to its closedposition. To this end, a cam 34, operatively connected to the movableswitch member is arranged to be moved into the path of the rear face 36of the latch member 26 to prevent counter-clockwise movement of thelatter when the switch is closed. As herein shown, the cam 34 is formedon the hub 32 of an arm pivotally connected to a shaft 42 journaled inthe casing l0 and the arm 40 is arranged to be rocked upon movement ofthe movable switch member through the linkage in cluding an arm 46secured to the shaft 22, a link 48 connected to the arm 40 and anintermediate arm 50 pivoted on a pin 52. In operation, when the switchis closed, the cam 34 will be rocked behind the latch member 26 to lockthe latter in its plug retaining position.

Provision is also preferably made in the preferred embodiment of theinvention, to prevent, in a novel manner, the switch from being closedunless the plug is inserted to its full depth in the receptacle. To thisend, a pivoted stop member 54 is provided, having an arm 5E yieldinglyurged in a counter-clockwise direction, into the path of the plug. Thestop member is pivotally mounted upon the shaft 28 and is urged into thepath of the plug by a coiled spring 58 having one end secured to thestop member 54 and the other end to a stationary part of the casing l0.Thus,

the tail 60 of the stop member 54 is normally urged into a position toprevent movement of the arm 40, by the engagement of the cam 34 so thatthe switch cannot be operated until the tail 60 is moved out of the pathof the cam. In operation, when the plug is inserted to its full depth inthe receptacle, the arm 56 is rocked in a clockwise direction viewingFigs. 1 and 4, thereby removing the tail 60 of the stop member from thepath of the cam '34. With the parts in the position, as illustrated inFig, 4, the switch may be closed, thereby rocking the cam 34 intolooking position through the linkage described.

As illustrated in detail in Fig. 5, the casing I0 is v provided with aslot 62 adjacent the receptacle and in alignment with the latch member26 in order to afford clearance for the key I5 and to insure the properregistration of the plug in the receptacle.

lit will .be observed that if the switch 1 I should in some mannerbecome closed without the plug inserted, such as by manual manipulationof the stop member 54, the latch member '26 will become locked in thepath of the plug and prevent the insertion thereof. Thus, it isimpossible to insert the plug unless the receptacle is dead and theswitch open.

From the description thus far it will be observed that the presentswitch affords a convendent and reliable method of locking a plug in thereceptacle by utilizing the polarizing key of a terminal plug ofconventional form as a locking member thereby eliminating the necessityfor providing special plugs, having special locking members providedthereon, when it desired to take advantage of this feature. The presentinvention also enables a simple and rugged construction of a pluglocking mechanism to be produced which is efiicient and reliable inoperation and capable of withstanding commercial use with minimumattention.

While the preferred embodiment of the invention has been hereinillustrated and described,

embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:

1. An electrical switch having in combination, a switch mechanismincluding a switch member movable to open and close said switch; acasing enclosing said switch mechanism; a receptacle connected to saidcasing; a terminal plug adapted to be removably inserted in saidreceptacle, said terminal plug having a polarizing key; a spring-pressedlatch pivotally mounted in said casing, said latch having a detentportion normally lying in the path of said polarizing key adapted to bedepressed when said plug is inserted in said receptacle and toautomatically return to its initial position and fall in behind saidpolarizing key when said plug is fully inserted in said receptacle; anda cam member for locking said latch in place after said plug has beeninserted in said receptacle, said cam member being connected with saidswitch member and being movable into locking position upon movement ofsaid switch member to closed position.

2. An electrical switch having in combination, a switch mechanismincluding a switch member movable to open and close said switch; acasing enclosing said switch mechanism; a receptacle connected to saidcasing; a terminal plug adapted to be removably inserted in saidreceptacle, said terminal plug having a polarizing key; a shaft in saidcasing; a spring-pressed latch pivotally mounted upon said shaft, saidlatch having a 'detent portion normally lying 'in the path of saidpolarizing key adapted to be depressed when said plug is inserted insaid receptacle and to automatically return to its initial position andfall in behind said polarizing key when said plug is fully inserted insaid receptacle; a second shaft in said casing; and a cam memberpivotally mounted on said second shaft for locking said latch in placeafter said plug has been inserted in said receptacle, said cam memberbeing pivotally connected with said switch member and being rotatableinto locking position upon movement of said switch member to closedposition.

3. An electrical switch having in combination, a switch mechanismincluding a switch member movable to open and close said switch; acasing enclosing said switch mechanism; a receptacle connected to saidcasing; a terminal plug adapted to be removably inserted in saidreceptacle; a spring-pressed latch pivotally mounted in said casing,said latch having an arm normally lying in the path of said terminalplug, said latch being adapted to be partially rotated by said plug upon7 insertion of said plug in said receptacle; and a cam member connectedwith said switch member, said latch having a stop element projectingtherefrom cooperable with said cam member to prevent movement of saidcam member and hence closing of saidswitch unless said plug is fullyinserted in said receptacle.

4. An electrical switch having in combination, a switch mechanismincluding a switch member movable to open and close said switch; acasing enclosing said switch mechanism; a receptacle connected to saidcasing; a terminal plug adapted to be removably inserted in saidreceptacle, said terminal plug having a polarizing key; a springpressedlatch pivotally mounted in said casing, said latch having a detentportion normally lying in the path of said polarizing key adapted to itwill be understood that the invention may be be depressed when said plugis inserted in said receptacle and to automatically return to itsinitial position and fall in behind said polarizing key when said plugis fully inserted in said receptacle; a cam member for locking saidlatch in place after said plug has been inserted in said receptacle,said cam member being connected with with said switch member and beingmovable into locking position upon movement of said switch member toclosed position; and a second spring-pressed latch pivotally mounted insaid casing, said second latch having an arm normally lying in the pathof said terminal plug and being partially rotatable by said plug uponinsertion of said plug in said receptacle, said second latch having astop element projecting therefrom cooperable with said cam member toprevent movement of said cam member and hence closing of said switchunless said plug is fully inserted in said receptacle.

5. An electrical switch having in combination, a switch mechanismincluding a switch member movable to open and close said switch; acasing enclosing said switch mechanism; a receptacle connected to saidcasing; a terminal plug adapted to be received in said receptacle, saidterminal plug having a polarizing key; a pivotally mountedspring-pressed latch in the path of said polarizing key adapted to bedepressed upon insertion of said plug and to automatically fall inbehind said polarizing key to yieldingly retain said plug in operativeposition when the latter is inserted in the receptacle; a pivotallymounted element having a locking cam formed thereon adapted to cooperatewith said latch to lock said latch behind said polarizing key when theswitch is closed; and means connecting said element with said movableswitch member, whereby when said switch member is moved to closedposition said element will be rotated so that the cam thereof assumes aposition to lock said latch in place.

6. An electrical switch having in combination, a switch mechanismincluding a switch member movable to open and close said switch; acasing enclosing said switch mechanism; a receptacle in said casing; aterminal plug provided with a polarizing key adapted to be removablyinserted in said receptacle; a shaft in said casing; a spring-pressedlatch pivotally mounted upon said shaft and having a portion in the pathof said terminal plug and adapted to be depressed when said plug isinserted into said receptacle; a second latch pivotally mounted uponsaid shaft in the path of said terminal plug, and a locking camcooperable with both of said latch members, said locking cam beingcooperable with the first latch member to lock said member in positionwhen the switch is in closed position and being cooperable with saidsecond latch member to prevent closing of the switch unless said plug isfully inserted in said receptacle.

CHARLES H. REYNOLDS.

